1 Nervous System: Part IV

The Central Nervous SystemThe Brain

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Can you survive when part of your brain is destroyed?

Now that you have their attention, explain this drawing to students. Phineas P. Gage (1823–1860) was an American railroad construction foreman now remembered for his improbable survival of an accident in which a large iron rod was driven completely through his head, destroying much of his brain's left frontal lobe, and for that injury's reported effects on his personality and behavior, effects so profound—for a time, at least—that friends saw him as "no longer Gage"

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2. Cells communicate with each other through direct contact with other cells or from a distance via

chemical signaling.

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Essential Knowledge 3.D.2

Neurotransmitters act as chemical signals

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Review the primary functions of the nervous system pointing out that today we will be focusing on the structures associated with the processing of the input.

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Central nervoussystem (CNS)

Brain

Spinal cord

Peripheral nervoussystem (PNS)

Cranial nerves

Ganglia outsideCNS

Spinal nerves

The vertebrate nervous system.

Nervous System Part IV: Central Nervous System & Brain TEACHER NOTES needs coding

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Gray matter

Whitematter

Ventricles

What accounts for the difference between white and gray matter?

Point out the ventricles, gray matter, and white matter. Emphasize that the gray matter is made of unmyelinated neurons while the white matter contains myelinated neurons. More than students need to know, but just in case you are asked…White matter, long thought to be passive tissue, actively affects how the brain learns and dysfunctions. Whilst grey matter is primarily associated with processing and cognition, white matter modulates the distribution of action potentials, acting as a relay and coordinating communication between different brain regions. http://en.wikipedia.org/wiki/White_matter

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• The central canal of the spinal cord and the ventricleof the brain are hollow and filled with cerebrospinal fluid

• The cerebrospinal fluid is filtered from blood and functions to cushion the brain and spinal cord as wel as to provide nutrients and remove wastes

Cerebrospinal Fluid

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Glia• Glia have numerous functions

including to nourish, support, and regulate neurons

– Embryonic radial glia form tracks along which newly formed neurons migrate

– Astrocytes induce cells lining capillaries in the CNS to form tight junctions, resulting in a blood-brain barrier and restricting the entry of most substances into the brain

No need for students to “memorize” the diagram, it is included solely for illustration.

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Efferent neuronsAfferent neurons

Central NervousSystem

(information processing)

Peripheral NervousSystem

Sensoryreceptors

Internaland external

stimuli

Autonomicnervous system

Motorsystem

Control ofskeletal muscle

Sympatheticdivision

Parasympatheticdivision

Entericdivision

Control of smooth muscles,cardiac muscles, glands

Use this graphic to describe the relationship between the peripheral and central nervous systems. It outlines the functional hierarchy of the vertebrate peripheral nervous system. Connect this flow chart to the image on the next slide so students will realize the information isn’t something different but is an extension of the same.

Nervous System Part IV: Central Nervous System & Brain TEACHER NOTES needs coding

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The peripheral system involves more than just muscles and eyes. It includes all of the sensory structures and the responding structures (glands, muscles, etc.)

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Efferent neuronsAfferent neurons

Central NervousSystem

(information processing)

Peripheral NervousSystem

Sensoryreceptors

Internaland external

stimuli

Autonomicnervous system

Motorsystem

Control ofskeletal muscle

Sympatheticdivision

Parasympatheticdivision

Entericdivision

Control of smooth muscles,cardiac muscles, glands

Revisit this graphic and think about using a specific example, let’s say you smell good food cooking and it makes your mouth water. What is your sensory receptor? (smell receptors) Where does the impulse travel to next? (along a sensory/afferent neuron to the brain) Once the information is processed by your brain where does information travel? (along motor/efferent neuron to salivary gland)

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The Vertebrate Brain Is Regionally Specialized

• Specific brain structures are particularly specialized for diverse functions

• These structures arise during embryonic development

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Human Embryonic Brain Developme

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Scroll over the bottom of the picture to activate the animation’s controls and press play. This movie is from a series of lectures given at the Howard Hughes Medical Institute (HHMI) in 2008. http://www.hhmi.org/biointeractive/neuroscience/dev_human_emb_brain.html The next goes into a bit more detail about human embryonic brain development.

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Embryonic brain regions Brain structures in child and adult

Forebrain

Midbrain

Hindbrain

Telencephalon

Diencephalon

Mesencephalon

Metencephalon

Myelencephalon

Cerebrum (includes cerebral cortex, whitematter, basal nuclei)

Diencephalon (thalamus, hypothalamus,epithalamus)

Midbrain (part of brainstem)

Pons (part of brainstem), cerebellum

Medulla oblongata (part of brainstem)

Midbrain

Forebrain

Hindbrain

Telencephalon

Diencephalon

MesencephalonMetencephalon

Myelencephalon

Spinal cord

Cerebrum Diencephalo

Midbra

PonsMedullaoblonga

CerebellumSpinal cor

ChildEmbryo at 5 weeksEmbryo at 1 month

Exploring: The Organization of the Human Brain Spend a few minutes explaining this . Additional pertinent details follow on the next few slides.

Nervous System Part IV: Central Nervous System & Brain TEACHER NOTES needs coding

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Brain structures in child and adult

Forebrain

Midbrain

HindbrainMyelencephalon

Cerebrum (includes cerebral cortex, whitematter, basal nuclei)

Diencephalon (thalamus, hypothalamus,epithalamus)

Midbrain (part of brainstem)

Pons (part of brainstem), cerebellum

Medulla oblongata (part of brainstem)

Midbrain

Forebrain

Hindbrain

Telencephalon

Diencephalon

MesencephalonMetencephalon

Myelencephalon

Spinal cord

Cerebrum Diencephalo

Midbra

PonsMedullaoblonga

CerebellumSpinal cor

ChildEmbryo at 5 weeksEmbryo at 1 month

Exploring: The Organization of the Human Brain Spend a few minutes explaining this slide. Additional pertinent details follow on the next few slides.

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Cerebrum Diencephalon

Midbrain

Pons

Medullaoblongata

CerebellumSpinal cord

Child

An enlargement of a child’s brain.

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Adult brain viewed from the rear

Cerebellum

Basal nucleiCerebrum

Left cerebralhemisphere

Right cerebralhemisphere

Cerebral cortex

Corpus callosum

Exploring: The Organization of the Human Brain

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Diencephalon

ThalamusPineal glandHypothalamusPituitary gland

Spinal cord

Brainstem

Midbrain

Pons

Medullaoblongata

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Motor cortex(control ofskeletal muscles)

Frontal lobe

Prefrontal cortex(decision making,planning)

Broca’s area(forming speech)

Temporal lobe

Auditory cortex (hearing)

Wernicke’s area(comprehending language)

Somatosensory cortex(sense of touch)

Parietal lobe

Sensory associationcortex (integration ofsensory information)

Visual associationcortex (combiningimages and objectrecognition)

Occipital lobe

CerebellumVisual cortex(processing visualstimuli and patternrecognition)

Nervous System Part IV: Central Nervous System & Brain TEACHER NOTES needs coding

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Language and Speech

• Studies of brain activity have mapped areas responsible for language and speech

• Broca’s area in the frontal lobe is active when speech is generated

• Wernicke’s area in the temporal lobe is active when speech is heard

• These areas belong to a larger network of regions involved in language

Just interesting: The first language area within the left hemisphere to be discovered is Broca's area, named after Paul Broca, who discovered the area while studying patients with a language disorder. Broca's area doesn't just handle getting language out in a motor sense, though. It seems to be more generally involved in the ability to process grammar itself, at least the more complex aspects of grammar. For example, it handles distinguishing a sentence in passive form from a simpler subject-verb-object sentence — the difference between "The girl was hit by the boy" and "The boy hit the girl.“ The second language area to be discovered is called Wernicke's area, after Carl Wernicke, a German neurologist who discovered the area while studying patients who had similar symptoms to Broca's area patients but damage to a different part of their brain. These people had damage to an area of the brain that affected speech comprehension called receptive aphasia. People with receptive aphasia also have difficulty recalling the names of objects, often responding with words that sound similar, or the names of related things, as if they are having a hard time recalling word associations.

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Information Processing• The cerebral cortex receives input from sensory

organs and somatosensory receptors• Somatosensory receptors provide information about

touch, pain, pressure, temperature, and the position of muscles and limbs

• The thalamus directs different types of input to distinct locations

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Frontal lobe Parietal lobe

Primarymotor cortex

Primarysomatosensorycortex

GenitaliaToes

Abdominalorgans

Tongue

Jaw

HipKnee

TonguePharynx

Head

Neck

TrunkHip

Body part representation in the primary motor and primary somatosensory cortices.

Nervous System Part IV: Central Nervous System & Brain TEACHER NOTES needs coding

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Primarymotor cortex

Toes

Tongue

Jaw

HipKnee

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Primarysomatosensorycortex

Genitalia

Abdominalorgans

TonguePharynx

Head

Neck

TrunkHipLeg

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Frontal Lobe Function

• Frontal lobe damage may impair decision making and emotional responses but leave intellect and memory intact

• The frontal lobes have a substantial effect on “executive functions” of thinking making decisions.

26 Created by:

Debra RichardsCoordinator of Secondary Science ProgramsBryan ISDBryan, TX

Nervous System Part IV: Central Nervous System & Brain TEACHER NOTES needs coding